Expected Speeds of Wireless with LEAP/VPN. Take 2

[croadc]

Hello all,

We're doing some testing of wireless networks here at my site. We have jumped on an all Cisco solution for now. For the sake of testing we are running 3 different configs using the following hardware:

Cisco Aironet 350 AP

Cisco Aironet 350 Wireless cards

Cisco 3030 VPN concentrator

A couple of Pentium II Class laptops with W2K

One of the tests we perform is a large file transfer (about 13Mb) from a wireless client to a wired client on our internal network using Microsoft Networking Protocols (i.e. drag a file on the wireless laptop to a shared folder on the wired system). My question is about transfer times. A 13Mb files takes these times to tranfer using the following configs:

Using LEAP and IPSEC - 21 minutes

Using IPSec Only (no LEAP) - 9 minutes

Using no encryption - 30 Seconds.

This all makes perfect sense to me, as I understand that the encryption process is software based and therefore processor intensive. That each encryption technique adds overhead. That 802.11 addes it's own overhead, etc... However, my management here is convinced that "there must be something wrong!" He feels that because when he surfs the web (small files, bursty traffic) in any of the 3 modes I've outlined above it's very fast, that large file transfers should be just as fast. (Sigh).

Does anyone have any empirical data I can use to try and convince this guy that this is the way it is, or is he right, and I AM doing somehting wrong.

Any help or comments are appreciated.

[eudechime]

You are absolutely correct on your overhead explanation. The link below was result of test bed on wireless, shared and switched network. There is a number if you are looking for number, though it depends on number of users. But since your he does not seem to believe you, may be this link will help.

http://www.cisco.com/warp/public/cc/so/cuso/smso/crn/ndgp_rg.htm

Good luck

Elias

[shaun.oliver]

To test the actual throughput speeds, use binary mode FTP (set up a server on the wired LAN, retrieve a file on the wireless laptop). Don't use a Windows file transfer as a test, they tend to be fairly inaccurate.

I haven't tried with IPSec, but with normal LEAP & 128-bit WEP, you can transfer a 10MB file in around 25 seconds (assuming the wireless laptop is the only wireless device in use on that AP).

As far as actual transfer times on an AP with a lot of users, it can be a lot slower (like a hub).